Range Report Rocky Mountain .338 275 grain BC’s

[COHotshots]

Hey, was wondering if you guys have any experience running these bullets or not. What was your observed bc’s? I was shooting these at 1670 yards and corrected the bc instead of the muzzle velocity because I feel very confident in the chronographed velocity. Went from .423 advertised to .328. That’s a pretty big drop and .328 seems low for 275 grain. Muzzle velocity is 2990 with 5 es